package designpattern.patterns.structure.proxy.rpc;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Method;
import java.net.ServerSocket;
import java.net.Socket;

public class RpcServer {

    public void export(Object service, int port) throws Exception {
        if (service == null) {
            throw new IllegalArgumentException("service instance == null");
        }
        if (port <= 0 || port > 65535) {
            throw new IllegalArgumentException("Invalid port " + port);
        }

        ServerSocket server = new ServerSocket(port);
        while (true) {
            final Socket socket = server.accept();
            new Thread(() -> {
                try {
                    ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                    ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                    try {
                        String methodName = input.readUTF();
                        Class<?>[] parameterTypes = (Class<?>[])input.readObject();
                        Object[] arguments = (Object[])input.readObject();
                        Method method = service.getClass().getMethod(methodName, parameterTypes);
                        Object result = method.invoke(service, arguments);
                        output.writeObject(result);
                    } catch (Throwable t) {
                        output.writeObject(t);
                    } finally {
                        output.close();
                        input.close();
                        socket.close();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }).start();
        }
    }

}
